From 2aced65bf86630e69c4d5bd5968be3bfe47db40d Mon Sep 17 00:00:00 2001
From: Harry Yang <harryy@codeaurora.org>
Date: Mon, 17 Jul 2017 11:44:37 -0700
Subject: [PATCH] qcom: qnovo: restart pulse train in stall state

There are a couple of cases where qnovo charging fails,

1. pulse train enable command register fails to write through, or
2. pulse engine fails to start and pulse train timer PTTIME does
   not start counting.

In either case, qnovo charging will stop. Here is the fix,

Write register twice when enabling pulse train, and
restart pulse train if PTTIME does not increase.

Change-Id: Ic235f8f2bc67fe577e42848ef623870c25b68256
Signed-off-by: Harry Yang <harryy@codeaurora.org>
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
---
 drivers/power/supply/qcom/qpnp-qnovo.c | 62 ++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/drivers/power/supply/qcom/qpnp-qnovo.c b/drivers/power/supply/qcom/qpnp-qnovo.c
index 69ea39ad5744..cf90f9041935 100644
--- a/drivers/power/supply/qcom/qpnp-qnovo.c
+++ b/drivers/power/supply/qcom/qpnp-qnovo.c
@@ -20,6 +20,7 @@
 #include <linux/of_irq.h>
 #include <linux/qpnp/qpnp-revid.h>
 #include <linux/pmic-voter.h>
+#include <linux/delay.h>
 
 #define QNOVO_REVISION1		0x00
 #define QNOVO_REVISION2		0x01
@@ -124,6 +125,8 @@
 #define USB_READY_VOTER		"USB_READY_VOTER"
 #define DC_READY_VOTER		"DC_READY_VOTER"
 
+#define PT_RESTART_VOTER	"PT_RESTART_VOTER"
+
 struct qnovo_dt_props {
 	bool			external_rsense;
 	struct device_node	*revid_dev_node;
@@ -161,6 +164,8 @@ struct qnovo {
 	int			dc_present;
 	struct delayed_work	usb_debounce_work;
 	struct delayed_work	dc_debounce_work;
+
+	struct delayed_work	ptrain_restart_work;
 };
 
 static int debug_mask;
@@ -354,6 +359,11 @@ static int pt_dis_votable_cb(struct votable *votable, void *data, int disable,
 	struct qnovo *chip = data;
 	int rc;
 
+	if (disable) {
+		cancel_delayed_work_sync(&chip->ptrain_restart_work);
+		vote(chip->awake_votable, PT_RESTART_VOTER, false, 0);
+	}
+
 	rc = qnovo_masked_write(chip, QNOVO_PTRAIN_EN, QNOVO_PTRAIN_EN_BIT,
 				 (bool)disable ? 0 : QNOVO_PTRAIN_EN_BIT);
 	if (rc < 0) {
@@ -362,6 +372,12 @@ static int pt_dis_votable_cb(struct votable *votable, void *data, int disable,
 		return rc;
 	}
 
+	if (!disable) {
+		vote(chip->awake_votable, PT_RESTART_VOTER, true, 0);
+		schedule_delayed_work(&chip->ptrain_restart_work,
+				msecs_to_jiffies(20));
+	}
+
 	return 0;
 }
 
@@ -1311,6 +1327,51 @@ static void status_change_work(struct work_struct *work)
 	qnovo_update_status(chip);
 }
 
+static void ptrain_restart_work(struct work_struct *work)
+{
+	struct qnovo *chip = container_of(work,
+				struct qnovo, ptrain_restart_work.work);
+	u8 pt_t1, pt_t2;
+	int rc;
+
+	rc = qnovo_read(chip, QNOVO_PTTIME_STS, &pt_t1, 1);
+	if (rc < 0) {
+		dev_err(chip->dev, "Couldn't read QNOVO_PTTIME_STS rc = %d\n",
+			rc);
+		goto clean_up;
+	}
+
+	/* pttime increments every 2 seconds */
+	msleep(2100);
+
+	rc = qnovo_read(chip, QNOVO_PTTIME_STS, &pt_t2, 1);
+	if (rc < 0) {
+		dev_err(chip->dev, "Couldn't read QNOVO_PTTIME_STS rc = %d\n",
+			rc);
+		goto clean_up;
+	}
+
+	if (pt_t1 != pt_t2)
+		goto clean_up;
+
+	/* Toggle pt enable to restart pulse train */
+	rc = qnovo_masked_write(chip, QNOVO_PTRAIN_EN, QNOVO_PTRAIN_EN_BIT, 0);
+	if (rc < 0) {
+		dev_err(chip->dev, "Couldn't disable pulse train rc=%d\n", rc);
+		goto clean_up;
+	}
+	msleep(1000);
+	rc = qnovo_masked_write(chip, QNOVO_PTRAIN_EN, QNOVO_PTRAIN_EN_BIT,
+				QNOVO_PTRAIN_EN_BIT);
+	if (rc < 0) {
+		dev_err(chip->dev, "Couldn't enable pulse train rc=%d\n", rc);
+		goto clean_up;
+	}
+
+clean_up:
+	vote(chip->awake_votable, PT_RESTART_VOTER, false, 0);
+}
+
 static int qnovo_notifier_call(struct notifier_block *nb,
 		unsigned long ev, void *v)
 {
@@ -1564,6 +1625,7 @@ static int qnovo_probe(struct platform_device *pdev)
 	INIT_WORK(&chip->status_change_work, status_change_work);
 	INIT_DELAYED_WORK(&chip->dc_debounce_work, dc_debounce_work);
 	INIT_DELAYED_WORK(&chip->usb_debounce_work, usb_debounce_work);
+	INIT_DELAYED_WORK(&chip->ptrain_restart_work, ptrain_restart_work);
 
 	rc = qnovo_hw_init(chip);
 	if (rc < 0) {